Panel Discussion on Scientific Opportunities in XAFS Research at the 4th GEN LSs

16:20

Closing

About the workshop

The advent and privileges of the 4th GEN light sources are high brilliance and transverse coherence that allows scientific opportunities made possible use of (1) focused beam (nanobeam), (2) uniform phase wavefronts and (3) ultra short pulses (100 fs). These superior capabilities are utilized individually or in combination allowing going beyond the current limitations toward new x-ray spectroscopy science such as spectro-imaging and photon-correlation spectroscopy for studies of slow dynamics in disordered materials. Although the power density is similar to the previous low emittance rings, beamline optics is going to face various challenges, energy scan of nanobeam and versatility in focus size to avoid soft sample damages. We anticipate that advances in time-resolved XAFS experiments utilizing short pulses will be another focus of this workshop, ranging from energy-dispersive setup to timing experiments at XFEL facilities represented by European XFEL.

As challenging issues are strongly dependent on the facility and/or beamline, it is important to overview different cases and intensive discussion by experts. The aim of the workshop is to discuss scientific opportunities in XAFS research at the 4th GEN light sources with different views and perspectives. In order to fully make use of superior specifications of the new light sources some challenging issues are to be recognized and solved. It is truly amazing that the 4th GEN light sources are rapidly increasing their family members following MAX IV; Sirius, Diamond II, SOLEIL II, SLS II, ALS-U, APS-U, Spring-8 II, PETRA IV… It is the organizer’s pleasure if this workshop will be a wonderful opportunity for bridging the generations of light sources. Lastly, but not least, it could be a nice opportunity to pay respect to the Mikael Eriksson (Maxlab) and MAX IV lattice design team for inventing a new lattice based on multibend achromat strategy.

About the panel discussion

Invited speakers represent different facilities with different specifications and thus may have different scientific contexts expecting the future of the 4th GEN light sources differently. Therefore these views would be quite topical and interesting to explore with a limited number of slides. The participants (invited speakers who are willing to participate) could be asked for two slides: one about the presently available methods/instruments evolved towards the 4th generation – how these techniques are expected to become better and the second one about presently impossible experiments (related to XAS/XES) enabled at the 4th generation – for which one’s imagination is welcome. Secondly, as PETRA IV is soon going to join the DLSR family, Dr. Edmund Welter (DESY) was invited to join the panel discussion.

An Introduction to XAFS Data Analysis with Athena and Artemis (and Larch)

Discussion: Python and Larch application developments for XAFS and beyond

16:00

Closing

About the workshop

This one-day session will provide an overview of XAFS data processing and EXAFS analysis using Larch. The session will begin with lectures on analysis methods, but students should have some familiarity with X-ray absorption spectroscopy. The course will emphasize interactive demonstrations of data processing and analysis of EXAFS spectra with practical tips for real analysis strategies for students to learn how to apply these methods to their own research. The session will include a discussion of using the scripting capabilities of Larch and Python. The last two hours of the session will feature presentations and discussions of current and future developments with Larch and Python.

Requirements

Each participant is expected to have own laptop. The Larch software is available at https://xraypy.github.io/xraylarch/ for Windows, MacOS, and Linux, and can be installed before the course, or during the first hour of the course.

Organized by Joshua J. Kas (University of Washington)

Schedule

09:00

Introduction to FEFF9 and JFEFF GUI

10:30

Coffee

11:00

DFT supported FEFF calculations

14:00

Lunch

About the Workshop

This hands on workshop will focus on using FEFF9 to simulate XANES and related spectroscopies. We will begin by instructing participants on the use of FEFF9 with the JFEFF GUI, from installation, to simple examples and tips. Participants will follow along on their own laptop. We will also talk about the combined use of DFT and FEFF to obtain more accurate calculated results and improved physical interpretation of data. Finally, if time permits, we will help participants in simulating XAS of some physical system of interest to them.

Schedule

About the Workshop

The workshop will focus on using GNXAS package for EXAFS data analysis. GNXAS is an advanced software based on multiple-scattering (MS) calculations and a rigorous fitting procedure of the raw experimental data. Its main characteristics are: atomic phase shifts calculations in the muffin-tin approximation based on atom self-consistent relativistic calculations, inclusion of inelastic losses through complex Hedin-Lundqvist potential, calculation of MS signals associated with two, three, and four atom configurations using advanced algorithms.

Requirements:

Attendants are expected to carry their own laptop and can possibly have already downloaded the GNXAS software. They may carry their own data, and possibly try to use GNXAS before the workshop. Software is freely available after registration. The page for downloading is: http://gnxas.unicam.it/pag_gnxas/gnxas_download.html.